The present invention relates generally to an adjustable socket-type wrench and, more particularly, to such tools particularly configured and adapted for the removal of an oil filter cartridge such as conventionally utilized on automobile and like engines.
As is well known, substantially all modern automobile and like internal combustion engines are provided with a threaded connection on the engine block for mounting of an oil filter cartridge for removing dirt and other debris and foreign matter from the lubricating oil as it is circulated through the engine cavities during operation. Draining and change of the lubricating oil from the engine, together with replacement of the oil filter cartridge, is a routine engine maintenance procedure which ordinarily must be performed at least once or more a year, depending upon the frequency and duration of normal engine operation.
While oil and filter cartridge replacement is intended to be a simple procedure to accomplish, it is common for the threaded connection between the filter cartridge and the engine to become frozen as a result of repetitive heat expansion and contraction of the engine and cartridge and the possible accumulation of debris in the threaded connection. Thus, although manufacturers typically recommend that oil filter cartridges be installed only by hand tightening, it is frequently impossible to remove a filter cartridge by hand after a period of use.
As a result, a number of tools of varying constructions have been developed for the specific purpose of creating a mechanical advantage in manually applying removal torque to an oil filter cartridge to loosen its threaded connection to an automobile engine. Perhaps the most common such tool currently in use has an elongate handle with a circular band or strap at one end for encircling and frictionally engaging the periphery of the oil filter cartridge for operation as a wrench-like tool to apply torque to the cartridge. Other conventional tools are configured as a full or partial cap adapted to fit over the outwardly exposed end of an oil filter cartridge for rotational operation by a conventional socket wrench handle or similar drive tool for applying removal torque to the filter cartridge. Other specialized oil filter tool constructions have also been proposed, such as disclosed in U.S. Pat. No. 4,643,053. Disadvantageously, however, such conventional tools sometimes do not provide sufficient frictional engagement with the cartridge periphery to avoid slippage of the tool with respect to the cartridge and are therefore sometimes incapable of dislodging an oil filter cartridge. Furthermore, while some of the aforedescribed tools are designed for diametric adjustment, the range of available adjustment is limited to that necessary to accommodate one particular type or size of conventional oil filter cartridge so that such tools are nevertheless incapable of use with all sizes of conventional oil filter cartridges.
It is accordingly an object of the present invention to provide an improved socket-type wrench having a self-adjusting gripping arrangement which is particularly adapted for non-slipping use in removing automotive oil filter cartridges of all conventional sizes.